ANTIVIRAL Flashcards
Acyclovir MOA
guanosine analog, is preferentially phosphorylated by viral thymidine kinase and inhibits
viral DNA polymerase, halting viral DNA synthesis by chain termination
TK is produced at a ? rate in herpes
infected cells than in noninfected cells
higher
Rapid intravenous infusion of acyclovir
reversible
obstructive nephropathy16
prodrug of its active metabolite, acyclovir
Valacyclovir
Valacyclovir vs Acyclovir
enhanced bioavailability
converts rapidly completely into acyclovir
Valacyclovir has been shown to be superior to acyclovir
shortening the duration of pain from post-herpetic
neuralgia associated with zoster patients
Longer intracellular half-life than acyclovir
Famciclovir
prodrug of penciclovir
Famciclovir
CMV retinitis in immunocompromised patients and for CMV prophylaxis in
transplant patients
Gancyclovir
PO Gancyclovir
has very poor bioavailability
Adverse effects Gancyclovir:
Bone marrow suppression, neutropenia, and thrombocytopenia; worsened
by concomitant administration of AZT
Foscarnet MOA
Noncompetitive inhibition of viral DNA polymerases at the pyrophosphate-binding site
Foscarnet active against viruses
resistant to acyclovir, famciclovir, or ganciclovir on basis of altered kinase activities
Does not require phosphorylation for antiviral activity
Penile erosions
Foscarnet
HSV or VZV infection resistant to acyclovir ganciclovir-resistant CMV
Foscarnet
Cidofovir MOA
Nucleotide analogue
• Does not require phosphorylation by virus, but is converted by host cell kinases to diphosphate
Cidofovir ADR
Renal—proteinuria and increased creatinine
Zidovudine AZT
preferentially inhibits HIV
reverse transcriptase rather than human DNA polymerase
Zidovudine SKIN ADR
dark streaks nails,
diffuse and oral hyperpigmented macules,
trichomegaly
Zidovudine ADR
Bone marrow suppression with subsequent anemia and granulocytopenia is
Didanosine
pyrimidine nucleoside analog
Didanosine basic environment absorption
CANNOT COMBINE
ketoconazole, itraconazole, or quinolone
antibiotics because requirement of an acidic environment
Abacavir moa
• A nucleoside reverse transcriptase inhibitor
• Causes a hypersensitivity reaction in
approximately 5% of treated patients → can be fatal
upon rechallenge of abacavir
Protease Inhibitors adr
lipodystrophy, which manifests as abnormal fatty deposits
known as the “buffalo hump” and “protease pouch
Protease Inhibitors MOA
Block the protease enzyme
responsible for final assembly of new
viral proteins
Indinavir can cause
gynecomastia and periungal pyogenic granulomas
Several HIV medications including indinavir, zidovudine, and lamivudine
have been reported to cause periungual/paronychial eruptions
resulting in PG-like lesions22,23
Interferons
• Given IV, IM, IL, or SQ
Effective in treatment of chronic hepatitis C and warts
Cytokines with broad antiviral, immunomodulating, and antiproliferative effects
Interferons dose-related ADR ;
• Side effects: Fever, chills, headache, myalgia, arthralgia, GI symptoms
granulocytopenia, thrombocytopenia,
various neurotoxicities, alopecia,
hepatotoxicity, and autoantibody formation
Interferons ADR
Imiquimod
Does not exhibit direct antiviral activity,
but instead exerts its action through immunomodulation
Induces cytokines,(TNF)-α, (IFN)-γ, (IFN)-α, (IL)-12, stimulation of a cell-mediated immune response
Podophyllin
• A crude cytotoxic extract from the
treatment OF
May apple plant, condyloma acuminatum
Podophyllin MOA
antimitotic, arresting cells in
metaphase by binding to the protein tubulin
